Polycystic ovary syndrome affects somewhere around one in ten women of reproductive age, and the average woman sees several clinicians across several years before anyone names it. The reason is that each symptom on its own gets a shrug. Irregular periods are normal for some people. Acne is teenage. Weight gain is lifestyle. It is only when you line them up that the pattern is obvious.
As of this year it also has a different name, and the reason behind the change explains the condition better than the old name ever did.
In May 2026 an international consensus renamed polycystic ovary syndrome to polyendocrine metabolic ovarian syndrome, or PMOS. The decision was published in The Lancet and presented at the European Congress of Endocrinology, after an eleven year process that consulted around 22,000 people and involved more than 50 patient and professional organisations, including the Endocrine Society. Health services have begun to follow, and the NHS now lists the condition as PMOS.
The old name was not just unloved, it was inaccurate in a way that caused harm. It implied pathological ovarian cysts, which most people with the condition do not have. It hid the hormonal and metabolic features that actually drive it. And it sent attention to the ovaries when the condition affects insulin, androgens, cardiovascular risk and mood.
The new name says what it is. Polyendocrine, because several interacting hormone systems are involved rather than one organ. Metabolic, because insulin resistance and the raised risk of type 2 diabetes and cardiovascular disease are intrinsic to it, not complications that happen later.
Expect both names in circulation for years. Your old letters and results will say PCOS, newer material will say PMOS, and they mean the same condition.
These are the features that cluster together:
Not everyone has all of these, and crucially you do not have to be overweight to have it. Lean PMOS is common and is diagnosed even later, because the stereotype gets in the way.
There are usually no cysts. What shows on an ultrasound are immature follicles, eggs that started to develop and stalled, sitting around the edge of the ovary. They are not painful, they are not dangerous, and they are not the problem.
The driver in most women is insulin resistance. Higher circulating insulin pushes the ovaries to make more androgens, those androgens interrupt ovulation, and the interrupted ovulation produces the irregular cycles and the follicles on the scan. That chain is why a condition named after ovaries is managed largely as a metabolic one, and why the new name puts the endocrine and metabolic parts first.
The Rotterdam criteria still apply, and require two of the following three, with other causes excluded:
Two practical points that save a lot of time. If you already have the first two, an ultrasound is not required to make the diagnosis. And in adolescents within a few years of their first period, ultrasound should not be used at all, because multi-follicular ovaries are normal at that age. Anti-Mullerian hormone is now accepted as an alternative to ultrasound in adults. ACOG's patient FAQ and the NICHD overview are both good things to read before the appointment.
Start a symptom search to map your symptom cluster and cycle history before your appointment, then take the summary with you. It is free, private and takes about a minute.
Investigation has two jobs: confirm the picture, and exclude the conditions that imitate it.
Weight and activity changes remain first line where weight is a factor, and the threshold is lower than people expect: a loss of around 5 to 10 per cent of body weight restores ovulation in a meaningful proportion of women. Resistance training matters here as much as cardio, because muscle is where insulin sensitivity lives.
Metformin improves insulin sensitivity and menstrual regularity, and is commonly used, particularly where glucose tolerance is already impaired.
The combined oral contraceptive pill regulates bleeding, protects the lining of the womb and improves acne and hirsutism. It does not treat the underlying insulin resistance, which is worth knowing rather than discovering later.
Inositol has reasonable evidence for improving insulin markers and cycle regularity, with a good safety profile. It is a sensible option to discuss, not a cure, and the quality of products varies enormously.
Letrozole is first line for fertility, ahead of clomifene, where conception is the goal.
GLP-1 medicines are the live question. None is approved for this condition as a diagnosis anywhere. What the data show is that real-world use of these drugs produced a median weight reduction of around 11.5 per cent at one year, and in a small study roughly 71 per cent of semaglutide responders regained normal menstrual cycles within six months, with the best cycle recovery seen when semaglutide was combined with metformin. That is promising and it is off-label.
Two cautions that matter more than the headline. Because ovulation can return, fertility can return suddenly in someone who assumed they could not conceive, so contraception needs discussing at the start rather than later. And these drugs must be stopped well before conception, typically around two months for semaglutide, so anyone planning a pregnancy needs a timeline agreed with their doctor. Our guide to how GLP-1 drugs work covers the class in more detail.
This is a long-term metabolic condition with a materially higher risk of type 2 diabetes, gestational diabetes, high blood pressure, abnormal lipids, fatty liver disease and obstructive sleep apnoea. Very infrequent periods also mean the lining of the womb is not shed regularly, which over years raises endometrial risk, and that is why clinicians care about cycle frequency rather than just about comfort.
The practical implication is that the diagnosis should come with ongoing metabolic monitoring, not a prescription and a goodbye. If you have been told to come back when you want a baby, that is not current practice. That shift in emphasis is precisely what the new name is meant to signal.
PCOS is now PMOS, and the rename reflects what it has always been: a hormonal and metabolic condition rather than an ovarian one. It announces itself through irregular cycles, androgen symptoms and insulin resistance, and is diagnosed on two of three criteria with other causes excluded. Ask for androgens, thyroid, prolactin, 17-hydroxyprogesterone, a glucose tolerance test and lipids, and expect long-term metabolic follow-up even when fertility is not the question.
Start a symptom search if this pattern sounds like yours, and track cycles, weight and symptoms in your Health Passport so you arrive with evidence instead of an impression.
This article is for general education and is not a substitute for professional medical advice. GLP-1 medicines are not approved for this condition and carry specific pregnancy precautions. Discuss diagnosis and treatment with a qualified clinician.
Air pollution symptoms look almost identical to a viral infection. How to tell a pollution cough from a cold, which exposures actually matter, what protects you, and the warning signs that need a doctor rather than a mask.
Most coughs clear in under three weeks. If yours has not, the cause list changes completely. Whooping cough is surging in 2026, and there are six other explanations worth knowing before you ask for antibiotics that will not help.
Fatty liver now affects roughly one in three adults and is usually found by accident on a scan or a blood test. What the new name MASLD means, why fibrosis matters more than fat, the FIB-4 score, and the two drugs approved since 2024.